Studies will be made on the effects of cationic surfactants and other compounds used in ophthalmology on the permeability and structure of the corneal endothelium and the consequent changes in corneal thickness. These studies will be made using the specular microscope, as would other investigations on the relative roles of the epithelium and endothelium in the maintenance of corneal thickness. The latter studies include measurement of fluid movement across either membrane when the opposite membrane is in contact with a non-aqueous solution, ensuing fluid exchange only across the membrane of interest. Investigations will be made of the effect of hypertonic and hypotonic solutions on the change in thickness of the corneal epithelium. Experiments will be performed to determine the membranic effects of various commonly used ophthalmic drugs on the permeability of the isolated ciliary epithelium of the rabbit eye; these studies would reveal the true effect of the drugs on the membrane without any influence from the many other operant parameters normally existing in the eye. Work will also continue on the establishment of dose-response relationships of the cannabinoids with the eye in relation to the intraocular pressure reducing effect.